In the process of implementing MULTI-VP model in EUHFORIA, we encountered a number of elemental flows that are sub-critical at \(0.1\)  AU (typically less than \(1\%\)  of the whole map, and up to a few percent in the most extreme cases). MULTI-VP cannot assure a priori that the solar wind solutions it computes are super-fast at all angular positions at the target altitude of \(0.1\)  AU, as required for EUHFORIA. To correctly feed the MULTI-VP data into the heliospheric part of EUHFORIA, we needed to transform these speeds to super-critical such that all MHD characteristic curves are out-going at 0.1 AU [1]}. The correction was done by interpolating the sub-critical fast magnetosonic pixels with their closest super-critical neighbors obeying the mass-flux conservation. Once super-criticality has been achieved at the boundary, we were able to study the \(v_r\) , \(n\) , \(T\) , \(B_{r}\)  maps there. The analysis of inner boundary maps allowed us to obtain a first-order estimation regarding the differences between the models. Moreover, it helped us understand how the two coronal models deal with different magnetograms.
